help with universal power adapter for laptops

I was given 3 old laptops by a friend who was moving. The only downside, the batteries are all dead and there is no power plugs, so I'm looking at getting a universal power plug which will work for all 3 - atleast to see if they are even worth keeping.

They are Compaq Presario 1620, HP Compaq nx9010, HP Pavillion zd7000

The only one that has any 'watts' on it is the HP nx9010 says 90w by the power adapter plug in

My question, when looking at these universal power plugs, what is the W that I should look for? I found one for 65W. Can I go too high? is there any way to find out what power should go with these? I know they are old so trying to get info on them is difficult.

Thanks.

 

I would look up the specs of each laptop online. Maybe even buy a replacement adapter on ebay. If you have too much wattage, the laptop can be damaged. Too little and it won't be able to keep the laptop on and power all the components.

 

Amazon.com: AC Adapter Charger for Compaq Presario 1620 2700T 1688 1692: Computers & Accessories

Amazon.com: NEW AC Adapter Power Supply Charger+Cord for HP/Compaq Business NX9010US NX9905 nx-9000us nx9000 nx9005 nx9008 nx9010 Pavilion xt100: Computers & Accessories

Amazon.com: Battery Charger+Cord for HP Pavilion ZD7000 ZV5000 Compaq Presario R3320: Computers & Accessories

I think thats it! And for 30 bucks!!

I just noticed the reviews for the middle charger werent all that great. Here is another one:
http://www.chargerbuy.com/replacement-hp-compaq-nx9010-ac-adapter-19v-4-74a.html#.UMtQem-dO68

 

Thank you, I was hoping to find 1 universal adapter that can be used for all 3 as I'm not even sure all 3 are worth keeping.

 

Haha well i guess ill just answer your original question then This looks like it should work

Rocketfish Netbook AC Power Adapter RF-AC9023 - Best Buy

The downside if you use this type of charger is that batteries not rated for the same amperage the charger puts out will be charged with too much power reducing the overall life of the battery. If you decide to keep them in the long run, OEM chargers are desireable. Otherwise, I dont see any downside to using something like the link above to test them.

 

Thanks. I'm not worried about the 'battery' life. I can use it with the power plug without problem. Thanks. I'll check the links.

 

I'm actually pretty sure that using a power adapter of a higher wattage will not have an adverse effect on the battery.

 

No it will not, a PSU of lower or higher voltage is asking for trouble though.

The Wattage represents the maximum that the PSU can give and it can be calculated as P = V*I where P is the power or wattage, V is the voltage and I is the current. If the laptop needs 50W at 19V, it will draw a current of 50W/19V=2.63A regardless of what the maximum current your PSU is able to deliver. If you have a PSU that has a maximum current of 12A at 19V, the draw on it will still only be 19V at 2.63A if you need 50W. The laptop is what determines the power that goes through the PSU and not the other way around. You can use any adapter at the right voltage provided it's amperage is equal or higher to the original adapter.

An adapter with a voltage too high on the other hand could damage your components.

 

@tijo, thanks for the help! I wasn't sure if laptops would only draw the watts required. So, @OP, the thing to check is the Amperage. A high amperage will charge the battery faster but reduce the life and total number of charge cycles the battery can handle. (But like you said, you really are not concerned with this)

Voltage shouldn't be a problem. Nearly all laptop chargers are rated for 100v-240v to be compatible with all part of the world. I have never run across a newer laptop charger that was not

 

It si the output voltage that is a problem, not the voltage at the outlet. Use an adapter that outputs 19V with a laptop that takes 14V and it won't be pretty.

 

Just stop it! You were corrected once already, but you keep making up new fairy tales. Every last thing you said here is 100% not true.

voltage x current (amps) = power (measured in watts). Therefore, since the voltage is a constant, and the laptop will only draw the amount of power it needs, it will draw more or less amps depending on how much power it is drawing.

 

@Qing, I understand what you are saying, but if that is the case, how would a rapid charger work? If you use a rapid charger for a phone or laptop, the difference is the amperage or the total power of the charger. The laptop/phone is able to draw more current in order to charge the battery faster. Dells for example offer a low current charger of 65W and high current of 90W. If your theory is correct, both chargers charge batteries at the same exact rate. In fact the 90W charger charges the battery faster because the laptop is able to draw more amperage to charge the battery. It is this concept I was referring to.

Correct me if I am wrong but laptops have an internal current limiting device. Therefore some laptops charge faster with high current chargers. This definitely was true for my apple Mac book. The supplied apple 60w charger charged my battery much slower than the 75 watt Mac book pro charger. Once the battery is fully charged the power/amperage does not matter as long as it exceeds the original charger rating. During charge; however, a higher power charger may in some cases charge the battery faster. Since laptops use lithium ion batteries and lithium ion battery life expectancy is reduced by quick charging, I stand by my original statement. Some battery life cycles may be reduced when using a higher power charger. The laptop however will be fine.

 

But you do know that the amount of battery cells and overall capacity of the battery has nothing to do with what power supply comes with a laptop, right? The power supply that comes with a laptop is generally based on how much power the laptop uses under load. My netbook has a 6 cell battery and a 40 watt power adapter, and you can buy a gaming laptop with a 6 cell battery and a 130 watt adapter. Dell gives you the option of a higher rated charger because it charges the same laptop faster and doesn't hurt anything. And the same model laptops with the same batteries often ship with different power adapters based on the power draw of the components installed. Obviously a power supply with a higher output is going to charge the battery faster. I never said it wouldn't. But the charging circuitry inside the laptop and battery is not going to overcharge the battery or charge it too quickly. And on top of everything, li-ion batteries can be safely charged quickly, so you really don't have any reason to say this!

 

I get what you are saying and yes I understand battery cells and capacities. I just mean that I would still be wary of using a laptop charger that is rated much higher than the original charger. This obviously is personal preference, but I have seen internal regulators fail, ruining expensive batteried. Lithium Ion batteries do not mix well with heat (the heat which is created when charging the batter at high speeds) and for this reason I was saying that "fast charging" a lithium ion battery all the time is creating an environment for failure. There are systems in place to protect the battery but I prefer to not continually test those systems.

Charging the battery faster, while it may be safe and the laptop will allow you to do it, does affect the life of the battery adversely, compared to the number of charges you will get with a trickle charger. Yes, technology is advancing and new technologies are being created to charge batteries, but the fact of the matter is that Lithium Ion batteries degrade due to heat. Faster charging produces more heat and deteriorates the battery quicker.

 

you can't charge a notebook battery faster. at least while plugged to the notebook due to the voltage regulators. you can try to charge it at a lower voltage to see what happens. it won't charge slower, it just won't charge.
charging faster is possible and imo I would do it if I needed. I do it all the time with my 18650 cells which are very similar to the ones found in notebook batteries. sure it will decrease their lifespan but by how much it depends on how often they are charged in that way and how they are used and how often they are balanced. temperature is also a big issue. I always have a fan blowing when I'm charging my cells in less then 30min.
they will not blow up or have any adverse effect on the notebook other then less battery time.
when I buy a new notebook I always buy at least 1 secondary battery.
the problem is that you can't do this with notebook batteries. batteries have a built in controller and you can't just charge it how you want it unless you take all the individual cells outside the enclosure.
but there are a very few noteboks that have battery and/or charger options with the ability to charge batteries faster. For example the lenovo t430. There's also some models with hotswap batteries capability. extremely usefull if you want to change batteries. Don't known why they don't implement it in every notebooks.

About universal PSU's there's no issue whatsoever with using them IF the wattage and amperage is the same as the original psu. just make sure you buy a good quality one because there are some on the market with very bad quality because they use cheaper parts with less quality and tolerances.
I had one cheap universal psu that blowed up. litteraly melted from the inside! gladly the notebook didn't suffered anything but it caused a short circuit.

 

First of all I'd ignore jsipe007.

As tijo says, you need to worry about two things (apart from basic stuff like polarity).

Correct voltage for device. They vary from 12-20V typically, and using even a slightly wrong one can damage notebooks so it pays to get it right.

Maximum draw of device vs the rating of the power supply. Pairing a device that draws 90W with a power supply that supplies 65W can be a lesson in 'honey, where's the fire extinguisher we bought?' especially if you buy an insufficiently protected PSU.

There really isn't much room for guesswork here Google the particulars of your devices and double check. A variety of universal adapters are available, but if you want one PSU for all, choose one that a) can be configured for the correct voltage for all your machines and b) delivers sufficient power for the highest-drawing device you have.

The only problem is, that a decent universal PSU may be on the high side for what you might want to spend.

 

I really do get what you guys are saying and I'm not trying to make this more complicated than it is. I was just intending to let the OP know that using a higher power charger could adversely affect battery longevity. That is all. He said he was not concerned with battery life and I was prepared to move on. Then I was accused of making false statements and I attempted to explain my view and experience. I apologize OP for creating a much more complicated response than you were hoping. I just was explaining that each time I charge my phone with a 1A charger (it normally uses 750mA) or each time I find a laptop charges faster with a high power charger, I know to some extent the battery life is deteriorating. It may not be noticeable day in day out but it can be an effect of using a high power charger.

 

Alright I think I'm starting to get it. My phone is charging apparently faster because it is able to power all the components and charge the battery at the highest rate as designed by the manufacturer. Is that right? If I power two phones down that are the same model and charge them both with a 750mah charged and a 1a charger, they will charge at the same rate, drawing the amperage/power set by the manufacturer. Does that found about right?

Yes, i am sorry for being so stubborn but I appreciate you guys pointing me in the correct direction!

That being the case, there is absolutely no downside to using a higher power charger. It will charge the battery at the intended rate while powering the components, all the while not exceeding the manufacturers charging spec on the battery